Patients were assessed at baseline and followed at day 1, 7, 30, 90 and 180 after PDT. At the baseline and post-PDT visits, BCVA was measured by certified optometrists with the Early Treatment Diabetic Retinopathy Study (ETDRS) logarithm of the minimum angle of resolution (logMAR) chart at 4 m or Snellen chart at 6 m being converted to logMAR equivalent for analysis. OCT recordings were performed using an OCT 3 machine (StratusOCT, Carl Zeiss Meditec Inc., Dublin, CA). Both vertical and horizontal scans of 6.0 mm centered on the fovea were obtained for measurement of central foveal thickness. OCT central foveal thickness was measured manually using the retinal thickness mode and is defined as the distance between the inner surface of the RPE and the inner surface of the neurosensory retina at the fovea. FA and ICGA were performed in all patients at baseline, month 1, and 3 after PDT. Additional FA and ICGA were carried out in patients with persistence or recurrence of CSC during the follow-up period. CSC was classified according to FA findings into two groups: 1) chronic CSC with serous retinal detachment and focal leakage (Group 1); or 2) chronic CSC with diffuse leakage that had an RPE transmission defect in early phase and diffuse angiographic leakage in mid to late phases (Group 2). Features of CSC in ICGA were delineated according to the original descriptions.